This invention relates generally to a compacting apparatus and more particularly to an apparatus for placing fill material in an underground void.
Various different apparatus heretofore have been used for filling mine shafts and the like with granular material. An early example of apparatus of this kind is to be found in U.S. Pat. No. 1,391,678 which discloses an apparatus employing conventional high and low pressure pumps used to fill underground voids with concrete or grout and is limited to the use of compacting material which can be pumped in this manner. Another type of known apparatus delivers a slurry of earth and water by gravity into subterranean cavities. Gravity feed obviously has limitations and is unsuitable in those instances in which gravity forces alone are insufficient to accomplish the compacting operation. More rdiscloses apparatus for impelling granular material against the sides of a passage by repeated impulses of pressurized air. This apparatus utilizes an outer casing to supply aggregate material into a cavity and utilizes air pressure to assist in the delivery of the material. However, this apparatus appears to be limited to a specialized work of the kind described and is structurally different and operates in a different manner from the present device. In addition to the above noted prior patents various other structures for filling underground cavities as well as structures including some of the general structural and operational features of the instant invention are disclosed in U.S. Pat. Nos. 2,372,957, 2,555,238, 2,684,231, 2,987,211, 3,207,492, 3,641,775 and 3,786,639.